采用原位拉曼/傅里叶变换红外光谱联用技术研究二氧化氮在氧化铈中的存储机制。

Mechanism of NO2 storage in ceria studied using combined in situ Raman/FT-IR spectroscopy.

机构信息

Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, Darmstadt, Germany.

出版信息

Phys Chem Chem Phys. 2013 Jun 21;15(23):9066-9. doi: 10.1039/c3cp51441b. Epub 2013 May 13.

Abstract

In situ Raman spectroscopy combined with quantitative FT-IR gas phase analysis was used to elucidate the mechanism of NO2 storage in ceria. At room temperature, NO2 exposure induces an immediate increase in the degree of ceria reduction accompanying nitrate formation. Two parallel reaction pathways for nitrate formation are identified. The presence of steam strongly influences the storage behavior by favoring the formation of free nitrates over bidentate/bridging nitrates. At 200°, faster free nitrate formation and gas phase NO formation is observed, while the NOx storage capacity of ceria is reduced from 0.27 to 0.16 mmol g(-1) CeO2.

摘要

原位拉曼光谱结合定量傅里叶变换红外气相分析用于阐明二氧化铈中 NO2 存储的机理。在室温下，NO2 暴露会立即引起二氧化铈还原程度的增加，同时伴随着硝酸盐的形成。确定了两种形成硝酸盐的平行反应途径。水蒸气的存在通过有利于形成游离硝酸盐而不是双齿/桥接硝酸盐，强烈影响存储行为。在 200°C 时，观察到更快的游离硝酸盐形成和气相 NO 形成，而二氧化铈的 NOx 存储容量从 0.27 降至 0.16mmol g(-1) CeO2。